Salt and wet-salt is long known. The conventional process to make said salt is an evaporative crystallisation of brine, followed by washing and drying steps. Said brine is typically produced by dissolving a natural source of NaCl in water. The brine will also contain K, Br, SO4, and/or Ca, which moieties are typically present in the source of NaCl. A disadvantage of the conventional process is that the salt obtained has imperfections in the crystal lattice and contains occlusions, being small pockets of mother liquor of the evaporative crystallisation process (present in cavities in the salt crystals). Due to these imperfections and occlusions, the wet salt, and the brine produced therefrom, is contaminated with compounds present in the mother liquor. In particular, the amount of K, Br, SO4, and/or Ca that is carried over is quite high. Hitherto, additional washing steps and drying steps, such as centrifuge steps, were employed, which are energy consuming, to reduce the levels of the contaminants.
When brine produced from the wet salt is employed in the modern membrane electrolysis cells, such contaminants can cause significant problems and lead to less economic electrolysis operations.
For these reasons, there is a need for improved wet salt, having a lower level of contaminants, which can be produced more cost-effectively and which can be used to make a brine for electrolysis processes. Surprisingly, the present inventors have found that wet salt compositions can be produced with a reduced level of K, Br, SO4, and/or Ca and using less energy in the washing operations.